RIASSUNTO
Summary
This paper highlights the major drilling problems encountered in the field development programmes offshore Malaysia from 1978 to mid-1983. The major problems identified were pipe sticking which was common in all the areas and top hole drilling problems encountered in a few fields offshore Sabah and Sarawak. problems encountered in a few fields offshore Sabah and Sarawak. Generally, the problems were related to drilling deviated wells through the soft and unconsolidated formations common in this region. Preventive measures employed by the Contractors hove been effective in overcoming these problems in the later years of the period under consideration. period under consideration
Introduction
Malaysia is currently producing all of its crude oil from her offshore oil fields located in three areas, i.e. offshore Te engganu, offshore Sarawak and offshore Sabah as shown in Figures 1, 2 and 3, respectively.
EPMI (Esso Production Malaysic Inc.), which is the major operator in offshore Terengganu, drilled a total of 180 wells from 1978 to mid-1983. In addition, 6 wells were also drilled by EMPI in Tembungo field offshore Sabah.
SSB (Sarawak Shell Berhad) and SSPC (Sabah Shell Petroleum Co.), on the other hand, are the major operators in offshore Sarawak and Sabah drilling 96 and 60 development wells respectively, for the some period.
In offshore Terangganu, the formations are predominantly massive siltstones and claystones, which are highly reactive to water and interbedded with hard shale streaks ad coal stringers.
The offshore Sarawak area is divided into four main geological provinces, i.e. the Baram Delta, Balingian, Central and South West provinces, i.e. the Baram Delta, Balingian, Central and South West Luconic. In the Baram Delta and Balangian provinces, the formation are mainly clastics where the main hydrocarbon accumulations are anticlinal and fault closures. The reservoirs in the Baram Delta are fluviomarine in nature, naturally depleted and are more continuous than those in the Balangian Province.
The Central and the South West Luconic provinces are characterised by extensive carbonate build-up and the traps are overlain by clastics from seabed to about 1371.5 m (4500')-ss.
The sediments in offshore Sabah area are mainly clastics and usually consist of alternating series of sand, silts and cloys. They are very soft and unconsolidated. Structurally, the area is very complex due to strong folding and faulting.
P. 12-40 P. 12-40